For increased efficiency and size reductions, switch mode power converters and inverters use high frequency switching techniques for power conversions. However, high frequency switching of power switches creates many undesirable circuit behaviors such as switch turn-on and turn-off losses, high voltage switching transient noise, and momentary short circuits of power switches. The results are often catastrophic, such as device failures, excessive heat generation within the power devices, and unwanted electromagnetic interference (EMI). Solutions to these problems are complex and often at the expense of reduced power conversion efficiency, increased size, and cost.
Turn-off related switching loss and dv/dt reductions are often interrelated and relatively easier to control by means of passive and active snubber circuits. Active snubbers are expensive, cumbersome, and difficult to implement. On the other hand, popular passive snubber schemes such as Resistor-Capacitor-Diode (RCD) snubbers waste significant energy, causing reduced power conversion efficiency and increased heat generation. Nonetheless, additional circuit solutions in conjunction with turn-off snubbers must be found in order to address the other undesirable features of switch mode power supplies.